1.4021+QT800 stainless steel vs 1.4028+QT850 stainless steel
Leave a message
What is 1.4021+QT800 stainless steel?
1.4021 (EN standard, corresponding to X20Cr13) is a martensitic stainless steel containing 12-14% chromium and 0.16-0.25% carbon. After QT800 processing (quenching at 980-1035°C + tempering at 625-675°C), it achieves a tensile strength of 700-950MPa and hardness of 25-30HRC, balancing good toughness and corrosion resistance. It is suitable for dynamic load applications like automotive engine valves and hydraulic pump shafts.
What is 1.4028+QT850 stainless steel?
1.4028 (EN standard, corresponding to X30Cr13) is a high-carbon martensitic stainless steel with 0.26-0.35% carbon and 12-14% chromium. After QT850 processing (quenching followed by low-temperature tempering at 150-370°C), it reaches hardness of 45-51HRC and tensile strength of 800-1000MPa, though with lower ductility. It is primarily used in high-wear scenarios such as injection molds, cutting tools, and gears.
1.4021+QT800 stainless steel vs 1.4028+QT850 stainless steel
1. Chemical Composition & Heat Treatment
| Property | 1.4021+QT800 (X20Cr13) | 1.4028+QT850 (X30Cr13) |
|---|---|---|
| Standards | EN 10088-3, ASTM A276 (420 modified) | EN 10088-3, ASTM A276 (420) |
| Carbon (C, %) | 0.16-0.25 | 0.26-0.35 |
| Chromium (Cr, %) | 12.0-14.0 | 12.0-14.0 |
| Molybdenum (Mo, %) | ≤0.60 | ≤0.60 |
| Heat Treatment | Quenched at 980-1035°C, tempered at 625-675°C (QT800) | Quenched at 980-1035°C, tempered at 150-370°C (QT850) |
2. Tensile & Yield Strength
1.4028's higher carbon content enables 15-20% higher tensile strength than 1.4021+QT800, but at the cost of reduced ductility.
| Property | 1.4021+QT800 (Annealed) | 1.4021+QT800 (QT800) | 1.4028 (QT850) |
|---|---|---|---|
| Tensile Strength (MPa) | 450-650 | 700-950 | 800-1000 |
| Yield Strength (MPa) | ≥205 | 500-600 | ≥600 |
| Elongation (%) | ≥20 | 12-13 | ≥10 |
| Reduction of Area (%) | ≥40 | 40-45 | 35-40 |
3. Hardness & Impact Resistance
1.4028's extreme hardness (45-51 HRC) makes it ideal for high-wear applications, while 1.4021+QT800 balances hardness with better impact resistance.
| Property | 1.4021+QT800 (Annealed) | 1.4021+QT800 (QT800) | 1.4028 (QT850) |
|---|---|---|---|
| Hardness (HB) | ≤223 | 25-30 HRC (230-280 HB) | 45-51 HRC (420-480 HB) |
| Charpy Impact (J, 20°C) | ≥40 | 20-30 | 10-15 |
| Fatigue Strength (MPa) | 240 (10⁷ cycles) | 320 (10⁷ cycles) | 380 (10⁷ cycles) |
4. Corrosion & Heat Resistance
Both grades offer comparable corrosion resistance, but 1.4021+QT800's lower carbon content reduces carbide precipitation risks.
| Property | 1.4021+QT800 | 1.4028 |
|---|---|---|
| Corrosion Resistance | Moderate in atmospheric/water; resists weak acids | Similar to 1.4021, but lower in chloride environments |
| Oxidation Temperature | Stable up to 400°C; oxidation rate ≤0.5mg/cm²·h at 800°C | Identical to 1.4021+QT800 |
| Intergranular Corrosion | Passes ASTM A262 Practice E (with proper heat treatment) | Vulnerable without post-weld annealing |
5. Machinability & Weldability
1.4021+QT800 offers 30% better machinability than 1.4028, making it more cost-effective for complex fabrications.
| Property | 1.4021+QT800 | 1.4028 |
|---|---|---|
| Machining Speed (m/min) | 100-150 (HSS tools); 200-250 (carbide) | 80-120 (HSS tools); 150-200 (carbide) |
| Weld Preheating | 150-200°C (low hydrogen electrodes) | 200-250°C (higher cracking sensitivity) |
| Post-Weld Treatment | Tempering at 600-650°C recommended | Tempering at 150-300°C to avoid softening |
Looking for pre-hardened stainless steel bars or plates? GNEE offers 1.4021+QT800 and 1.4028+QT850 in customizable lengths, cut to size and with test certificates such as EN 10204 3.1B report, PMI spectral analysis and ultrasonic testing (JB/T 4730.3-2005 Class I).
Product Forms Supplied by GNEE
| Product Form | Available Grades | Condition / Processing |
|---|---|---|
| Hot Rolled Stainless Plate | 1.4021+QT800 / 1.4028+QT850 | Thickness 4–60 mm, cut-to-size available |
| Cold Rolled Stainless Strip | 1.4021 / 1.4028 (+A or +QT) | Thickness 0.3–3 mm, supplied in coils or flat sheets |
| Round Bar / Rod | Ø8–200 mm | Annealed or quenched & tempered; rough turned or precision machined |
| ground round bar | 1.4021+QT800 / 1.4028+QT850 | H9–H11 tolerance, suitable for precision shaft assemblies |
